Brazilian Critical Minerals gets thumbs up for rare earths field trial

• Brazilian Critical Minerals secures approval to use magnesium sulphate for its Ema in-situ field pilot trials
• Trials will seek to validate results from laboratory testing while testing in-situ permeability and leachability of the clays hosting REE
• Extensive final water washing of weathered profile to provide information for environmental permitting

Special Report: Brazilian Critical Minerals has the opportunity to validate the hydrogeological model and laboratory results for its Ema rare earths project after securing approval to use magnesium sulphate for field pilot trials.

Approval from the Environmental Protection Institute of Amazonas state will also allow valuable additional information on the leach characteristics of the REEs to be obtained while providing data for use in the environmental permitting process.

It enables Brazilian Critical Minerals (ASX:BCM) to kick off the permeability field pilot trials to begin once site set-up at the 934Mt Ema project is completed.

Personnel and all required materials and equipment have been mobilised to site, with electrical and mechanical installation in progress.

“We are now one step closer and within sight of the finishing line towards our goal of rapidly developing the lowest capex and opex and only ISR rare earth project outside of Asia,” managing director Andrew Reid said. 

“We are very thankful to IPAAM and pleased to have received this vitally important permit which now allows us to inject and fully test, in-situ, the permeability and leach characteristics of the clays utilising MgSo4 which will assist in determining the expected rate of extraction of the rare earths.”

A recent scoping study found that Ema could produce close to 100,000t of rare earths over 20 years with life of mine costs of US$6.15/kg total rare earth oxides and US$16.95/kg neodymium and praseodymium – making the US$55m development the cheapest rare earths mine to build and run globally.

Test objectives

The field trial conducted by WSP Brazil seeks to validate all current laboratory work completed to date and to fine tune the extraction sequence developed for the drilling and injection of reagents by assessing the in-situ permeability and leachability of the clay profile hosting the rare earths.

“This phase of work is hugely important to inform our next study phase, in being able to design the detailed rare earth extraction system based on clay conditions and in-situ data,” Reid said.

On the back of expected positive results, the company plans to produce a mixed rare earth carbonate from the collected residue, which will be provided to strategic partners for quality control testing and to progress the execution of offtake agreements.

Tests to date have demonstrated a degree of permeability within the weathered clays that allows solution flow and the ability to ionically recover rare earths into solution.

Previous metallurgical recoveries averaged 68% magnet REOs, some of the highest for these types of deposits anywhere in the world, while a column test run by ANSTO to mimic conditions of temperature, pressure, density and moisture returned 74% MREO recovery.

The trial is expected to take several months to allow for various scenarios to be fully tested.

It will include extensive final water washing of the weathered profile to provide key information for the environmental permitting process.

This article was developed in collaboration with Brazilian Critical Minerals, a Stockhead advertiser at the time of publishing. 

This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.